In terms of water intrusion... this is related to the water table and grade of your yard (and soil type) more than the crawl space elevation. 

Don't surprise the tenant with unnecessary intrusions.

If it's not too intrusive would you be able to detail a few numbers?

Instilling fear through the media helps pave the way for citizens to give up their rights and go along with more intrusive government.

If you have a monitored alarm an intrusion will be responded to immediately and treated like a burglary, rather than responded to 2 weeks later after the person has had plenty of time to change the locks and move in.  

Make it as un-intrusive as possible and if they don't use it plug the stand pipe to avoid the trap water from drying up.

They can be noisy and intrusive, from what I've heard.

Haynes - I'd like to buy your real estate that has a code violationHello - excuse the intrusion - I am interested in making money off of your property - will you sell it to me for nothing down, take back some owner financing and give me immediate possession with a delayed settlement?

In furtherance of such obligation, TENANT AGREES TO PERFORM THE FOLLOWING:1.To keep the Premises free from dirt and debris that can harbor mold;2.To inspect the Premises regularly for the indications and sources of indoor moisture;3.To immediately report to Landlord any discoloration evidenced on walls, floors, or ceiling and/or any water intrusion, such as plumbing leaks, drips or flooding;4.To not air dry wet clothes indoors;5.To always utilize stove hood vents when cooking items that may cause steam;6.When showering/bathing, to always utilize the bathroom fan and to notify Landlord of any nonworking fan;7.To water plants outdoors;8.To notify Landlord in writing of overflows from bathroom, kitchen or any other water source facilities, especially in cases where the overflow may have permeated walls, flooring or cabinets;9.TO IMMEDIATELY WIPE DOWN ANY WATER OR CONDENSATION THAT APPEARS AND/OR DEVELOPS ON ANY AREA OR ANY SURFACE;10.To clean upon first appearance, any mildew from condensation on window interiors, bathroom & kitchen walls, floor and/or ceilings.

Likeplumbing not up to code - improper venting, wrong pipes or sizes used, galvanized pipe, copper pipe in slab etc.undersized framing, spans to long, dry rot, termite damagefoundation cracks, settlement, sill plates rottingasbestos in tiles, plaster, popcorn ceilings, pipe wraps, vent wraps, old furnace insulation. electrical grounds missing or improper, overloaded circuits, old panel, undersized panel, outlets not to code, aluminum wire, nob and tube wiremold in crawlspaces, basement, atticbad drainage in yard, water intrusion spots on house and foundation.oil tank in ground, radon testThese are just a very few things that you may not pick up if you don't know what to look for.And as previous said any findings are used to negotiate on price and/or save you from a big ticket item like asbestos removal, structure, water problems etc.